chore(tests) Make tests use local code

Create a symbolic link so that tests run against local repo code
and not npm-installed versions.
docs(readme) correct test-app instructions

Correct README.md so that it tells the user to run dpd from the right directory.
Merge pull request #300 from cayblood/update_readme

docs(readme) correct test-app instructions
Merge pull request #299 from cayblood/make_tests_use_local_code

chore(tests) Make tests use local code
feat(next): add next function throughout route workflow
feat(server): add middleware support through server & router